ISM Coordinate Mapping with Revit Structure

ISM Coordinate Mapping with Revit Structure

Background

In a situation where you need to start a project and work on both the Revit model and an analysis model independently of each other, ISM can be used to later import the structural elements from the analysis model.

The Revit model location can be based on the Project Base Point or a Survey Point. It can be offset from the origin point in the x, y or z direction. Your analysis model origin might be located at a 0, 0, 0. How do you align the two models when you import the analysis model into Revit?

Steps to Accomplish

1. Create an ISM repository from your analysis model. (See the analysis program help file for information on exporting a repository from a particular program.) 
2. Import the ISM repository into Revit. (See the ISM Revit Plug-in Overview on Bentley Communities.)
   
3. Once the ISM model is imported into the Revit model it is probably not in the correct location. You need to pick a landmark in the Revit model and measure the location of a corresponding element that was imported, from the repository, in the x, y, and z directions. This could be a column, a foundation or anything that was modeled in the same location in both models. When recording the dimension, pay attention to the positive or negative location in reference to the Revit model.
4. Do not save the Revit model. Instead use Undo to revert to the pre-import state of the model by selecting ISMRevitLink_root from the undo list.

Now to import the analysis model in at the correct location.

1. Use the Update From Repository command. When the ISM Revit Link dialog opens click on the Advanced button at the bottom of the dialog.

Enter the dimension you took earlier. Note any large dimensions may need to be entered as inches if it will not accept feet and inches.

Import the repository using the same steps as before.

Best Practices

1. When using Update From Repository is used the existing Revit model is exported out to be compared with the repository. All of the exported elements will be shown as having been deleted. In Structural Synchronizer, sort the Status column in the table on the right side of the screen, select all of the deleted elements and Reject the change. Use the filter to turn off the visibility of the rejected elements so only the Added elements are shown.

2. If column grids were added in the repository from the analysis model you will want to Reject those also. If the column grids originally came from the Revit model they will reset any adjustments you made to their position since the time they were exported. If they did not come from the Revit model, they will be imported into Revit. If they have the same grid line mark as an existing grid in the Revit model the grid line will be imported but the label will be appended with a # sign